IFTTT: card colors: add an actual white entry

To unset the color through the IFTTT, we need a white entry.
However, we do not want to show the white enry in the hamburger
`Set Color` entry.

We can also give the `white` capability to the API, it won't hurt
and be more straightforward.

client/components/cards/cardDetails.jade

@@ -339,9 +339,10 @@ template(name="cardMorePopup")
 template(name="setCardColorPopup")
   form.edit-label
     .palette-colors: each colors
-      span.card-label.palette-color.js-palette-color(class="card-details-{{color}}")
-        if(isSelected color)
-          i.fa.fa-check
+      unless $eq color 'white'
+        span.card-label.palette-color.js-palette-color(class="card-details-{{color}}")
+          if(isSelected color)
+            i.fa.fa-check
     button.primary.confirm.js-submit {{_ 'save'}}
     button.js-remove-color.negate.wide.right {{_ 'unset-color'}}
 

client/components/cards/cardDetails.js

@@ -601,6 +601,9 @@ BlazeComponent.extendComponent({
   },
 
   isSelected(color) {
+    if (this.currentColor.get() === null) {
+      return color === 'white';
+    }
     return this.currentColor.get() === color;
   },
 

client/components/cards/cardDetails.styl

@@ -146,6 +146,10 @@ card-details-color(background, color...)
   if color
     color: color !important //overwrite text for better visibility
 
+.card-details-white
+  card-details-color(unset, #000) //Black text for better visibility
+  border: 1px solid #eee
+
 .card-details-green
   card-details-color(#3cb500, #ffffff) //White text for better visibility